The Echo effect combines frames from different times in a clip. The Echo effect has a variety of uses, from a simple visual echo to streaking and smearing effects. The results of this effect are visible only if the clip contains motion. By default, any previously applied effects are ignored when you apply the Echo effect.

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Original image (left), with low echo values (center), and with increased number of echoes (right)

Echo Time (seconds)

The time, in seconds, between echoes. Negative values create echoes from previous frames; positive values create echoes from upcoming frames.

Number of Echoes

The number of echoes. For example, if the value is 2, the result is a combination of three frames: the current time, the current time + Echo Time, and the current time + (2xEcho Time).

Starting Intensity

The opacity of the first image in the echo sequence.

Decay

The ratio of the opacity of an echo to the opacity of the echo preceding it in the echo sequence. For example, if Decay is 0.5, then the opacity of the first echo is half of the Starting Intensity; the second echo is half that, or one quarter of the Starting Intensity.

Echo Operator

The blending operation used to combine the echoes.

Add

Combines the echoes by adding their pixel values. If the starting intensity is too high, this mode can quickly overload and produce streaks of white.

Maximum

Combines the echoes by taking the maximum pixel values from all of the echoes.

Minimum

Combines the echoes by taking the minimum pixel values from all of the echoes.

Screen

Emulates combining the echoes by sandwiching them optically. This setting is similar to Add, but it won’t overload as quickly.

Composite In Back

Uses the echoes’ alpha channels to composite them back to front.

Composite In Front

Uses the echoes’ alpha channels to composite them front to back.

Blend

Averages the echoes.